crisis in syria may be deepening, but there are also signs of a potential breakthrough. sources tell cbs news the united states has detected signs that syria's government is preparing chemical weapons for possible use. >> secretary of state clinton is holding an unscheduled meeting in ireland with the special envoy to syria. it is a sign that russia may be switching sides to put pressure on syria to stop the fighting. margaret brennan is in dublin covering those talks. good morning, margaret. do you think this is a sign of a diplomatic breakthrough? >> reporter: norah, it's a sign of a possible diplomatic breakthrough. u.n. envoy to syria is flying here to dublin for this last-minute meeting with secretary of state hillary clinton and the russian foreign minister. it may signal that russia is finally willing to take u.n. action to send a message to bashar al assad to stop the killing. russia one of syria's few remaining allies and so far have agreed to any interactions to stop the killing of thousands of people. >> charlie rose here. the reporting that they're mixing the